Method of making hollow leather articles



April 11, 1944. s, MARX 2,346,318

METHOD OF MAKING HOLLOW LEATHER ARTICLES Filed March 21, 1942 2 Sheets-Sheet 2 ATTORNEYS Patented Apr. 11, 1944 METHOD OF MAKING HOLLGW LEATHER ARTICLES Guilherme Siegfried Marx, Rio de Janeiro,

' Brazil Application March 21, 1942, Serial No. 435,660 In Brazil April 18, 1941 Claims.

This invention relates to the manufacture of a leather product from hides and skins.

It is well known that the number of industrial uses heretofore made of tanned hides and skins has been rather limited. Outside of the shoe and saddlery industries and the manufacture of machine belting, leather or tanned slnns have had but little application as a raw material.

The present invention opens a much wider field of use for hides and skins by providing a cheap leather product and a simple and inexpensive method of converting a hide or skin, or a portion thereof, into such product. The product may constitute a finished or partly finished useful article or a raw material to be supplied to manufacturers from which numerous useful articles may be made.

The operations performed on the hide or skin, or portion thereof, to convert it into the product considerably increase its area, and also increase its flexibility and elasticity.

In accordance with the preferred way of practicing the invention a piece of tanned leather, which is still in a wet or damp state from the tanning treatment, is provided with slits throughout at least a portion of its area, and is then stretched on a suitable frame until the piece of leather assumes the required size, or on a suitable mold until it assumes both the required size and the required shape. The leather is maintained in its stretched condition until it dries. The stretching of the leather further opens the slits to form numerous openings throughout the area of the stretched piece of leather, the size and shape of such openings, and their relative spacing, depending upon the length, relative spacing, and disposition of the original slits and also upon the direction in which the stresses act on the leather during the stretchin operation. The leather upon drying in its stretched condition acquires a permanent set and remains in its stretched state. If the leather is stretched in its own plane on a suitable frame it remains perfectly flat and if it has been stretched and shaped on a mold it maintains the shape to which it is molded. In either case the leather is rendered more flexible and more elastic.

In order that the method, and the nature of the product, may be clearly understood they will be described in connection with the accompanying drawings, in which:

Figure 1 is a plan view of a piece of leather which has been provided with slits and that is ready to be stretched; 1

Fig. 2 is a plan view of the same piece of leather after it has been stretched in its owrr plane to the required size;

Figs. 3 to 8, inclusive, are plan views illustrative of the way in which different arrangementsof slits will produce different kinds and arrangements of openings in leather pieces, each of" which has been stretched in its own plane, Figs. 3, 5 and 7 representing pieces of slit leather before stretching and Figs. 4, 6 and 8 representing respectively the same pieces of leather after stretching;

Fig. 9 is a plan view of a part of a leather brassiere, the slit portions of which have been shaped on a mold and simultaneously stretched; and

Fig. 10 is a perspective view of the brassire shown in Fig. 9.

Referrin first to Figs. 1 and 2, a piece of leather I, after it has been tanned, and while it is still in a wet or damp state from the tanning treatment is provided with a number of slits shown at 2. These slits may be formed in the leather by hand or by any suitable mechanical Fig. 2 represents the piece of leather after it has been stretched. The slits permit the leather to stretch considerably, as shown in Fig. 2, and they open up to form openings 2'. Slits having an arrangement and spacing of the kind shown in Fig. 1 will produce, in the stretched leather, somewhat square-shaped openings of the kind shown in Fig. 2 provided the leather is stretched enough. The leather may be stretched a relatively large amountto increase the area considerably and produce relatively large openings in the stretched leather, or the leather may be stretched a lesser amount in which case the openings in the stretched leather will, of course, be smaller and have a somewhat different shape.

The leather is allowed to dry on the frame and when removed will have a permanent set and will retain its stretched and flat condition.

Figs. 3 to B are illustrative of how openings of other kinds and shapes may be obtained in the stretched leather by other arrangements of slits. Inclined overlapping slits, of the kind indicated at 3 in Fig. 3, will produce openings in the stretched leather having the appearance of those shown at 3' in Fig. 4. If the slits have the length, disposition, and spacing, of those shown at 4 in Fig. 5, openings l having a somewhat diamond shape will be formed in the stretched leather, as shown in Fig. 6. If the piece of leather is provided with slits having the length, disposition, and spacing, of those shown at 5 in Fig. '7, the openings 5 formed in the stretched leather will have a somewhat oval shape, as indicated in Fig.

'8. The leather product produced by the method hereinbefore described has a much larger area than the original piece of leather and is more flexible and elastic. In some cases the piece of,

stretched leather may be regarded as the finished article where it is useful as such and no further operations have to be performed upon it. If further operations upon it are required to convert it into a finished article, the stretched leather may be regarded as a raw material which is useful in the manufacture of many different articles. The stretched leather may be used for, or in the manufacture of, chair seats, substitutes for bed springs, mattresses, the webbing for cots, belts for transmitting power as well as belts for wearing purposes, conveyors, horse girths, and many other things. If desired the slit leather can be used in the wet state and stretched directly on the furniture and allowed to dry thereon.

While the particular slits shown in the drawings are straight and parallel, it will be understood that if openings of some special shape are desired in the stretched leather it may be necessary to use curved slits, or slits disposed in some other way than in parallel relation. In fact, if necessary, holes or openings punched, stamped, or cut in the leather in any suitable way may be used in place of slits. Such openings should, of course, be of such a nature that they are capable of being made wider when the leather is stretched.

The size and shape of the slits, openings, or cuts in the unstretched leather, and their disposition and spacing, will vary according to the desired shape and size of the openings in the stretched leather and according to the purpose for which the final product is required and the increase in area desired.

Instead of stretching the slit leather in its own plane, as hereinbeiore described, the slit leather while still damp from the tanning treatment may be shaped on a suitable mold and allowed to dry thereon, as disclosed in Letters Patent No. 2,294,474 issued September 1, 1942, on an application filed inmy name. The stretching of the leather to further open the slits may result from the molding operation, orif" desired; the piece ofdamp slit leather may be stretched in its own plane and thereafter, while still damp, molded to the desired shape without any substantial additional stretching during the molding operation, the shaped piece of leather then being allowed to dry on the mold.

As an example of an article which maybe made by stretching and shaping the slit leather on a mold, there is illustrated in Figs. 9 and 10a part of a leather brassiere made in this fashion. The openings 6 have resulted from molding a piece of slit leather in such away that it is shaped'to form the two bulges best shown in Fig. 10, the.

leather being stretched during the molding operation to thus shape it and to. further open the slits. originally occurring where the openings now appear. A marginal portion '1 of the leather, as well as the connecting mid-portion 8, which were not, provided with slits, remainflat and help preserve the bulging form of the slit portions of the leather.

Many other articles, such as shoes, gloves, and the like can be produced in a similar manner.

It will be observed from Figs. 9 and 10 that when the leather is stretched on a mold all of the slits will not necessarily open to the same extent or form openings of the same final shape. The extent to which any given slit will open, and its final shape, will depend not only on the amount ofstretch imparted to the leather at the slit but also the direction in which the stresses incident to the molding operation act on the leather around the slit.

A piece of leather that has been tanned and allowed to dry and then slit and stretched, either on a frame or on a mold, as hereinbefore described, would not keep its shape or he as flat as leather that has been slit and stretched while it is still wet from the tanning treatment and that has been allowed to dry in its stretched condition. However, if desired raw leather may be used without tanning but in that case the final product will have less elasticity. Moreover, the

slits may be made in a piece of raw leather which is thereafter tanned and then stretched while still wet or damp from the tanning treatment as described above.

Chrome tanning is preferred but other tanning treatments may be used, such for instance as oil tanning.

My expanded or stretched leather might be regarded as leathernetting. To duplicate a piece of such leather netting of a given size by stamping or punching openings of the final size and shape in a piece of leather would, of. course, require a much larger piece of leather to start with, and there would be much wastage due to the portions stamped from the leather. By utilizingthe method herein. disclosed, a relatively small piece of leather can be stretched or expanded so that it has, in some instances, several times its original area, without any wastage at all.

The original cuts formed in the leather will be referred to in the, claims as elongated cuts. It should be understood that this expression includes not only slits but also openings or holes of the kind referred to above which are capable of being made wider when the leather is stretched in a direction to further open them.

I claim: I

1. The method of making a hollow leather article which comprises molding and stretching a piece of tanned leather provided with elongated cuts distributed over at least a portion of its area, such molding and stretching being performed while the leather is still wet from the tanning treatment and serving to further open said cuts, and allowing the leather to dry on the mold while maintained in its stretched condition.

2. The method of making a hollow leather article which comprises molding and stretching a. piece of chrome-tanned leather provided with elongated cuts distributed over at least a portion of its. area, such molding and stretching.

being performed while the leather is stillwet from the chrome-tanning treatment and. serving to, further open said cuts, and allowing the leather to dry on the mold while maintained in its stretched condition.

3. The method of making. a hollow leather article from. leather-that has been tanned which comprises providing a piece of suchleather while:

still wet from the tanning treatment with a number of elongated cuts distributed over at least a portion of its area, and also while the leather is still wet from the tanning treatment molding and stretching it to further open said cuts, and allowing the leather to dry on the mold while maintained in its stretched condition.

4. The method of making a hollow leather article which comprises providing a piece of leather with elongated cuts distributed over at least a portion of its area, tanning the leather thus cut, and while the leather is still wet from the tanning treatment molding and stretching it to further open said cuts, and allowing the leather to dry on the mold While maintained in its stretched condition. 

